Stepped-reflector antenna for satellite communication payloads

A reflector for being illuminated by at least one feed, the reflector comprising:

• a central region;
• and
• a first annular region with an annular width of w1 surrounding the central region, the first annular region axially stepped a height h1 above the central region,
• wherein h1 is approximately equal to
• m
• 1
• ×
• [
• Φ
• 1
• ±
• (
• ϕ
• ⁡
• (
• Θ
• =
• 0
• )
• -
• ϕ
• ⁡
• (
• Θ
• =
• Θ
• 0
• )
• )
• ]
• ×
• π
• 180
• ×
• λ
• 2
• ⁢
• π
• ×
• 1
• 2
• ,
• where m1 is a positive odd integer,
• Φ1 is a desired amount of phase shift of an outer region of a phase front for reflecting off of the reflector,
• φ is a feed phase contribution for an angle Θ, and
• Θ0 is an angle formed between an axis of the at least one feed and a line connecting a phase center of the at least one feed and an inner edge of the first annular region.

A multiple-beam antenna system, comprising:

• a reflector having a central region and a first annular region, the first annular region having an annular width w1 surrounding the central region, the first annular region axially stepped a height h1 above or below the central region;
• and
• at least one multiple-band feed for illuminating the reflector,
• wherein the at least one multiple-band feed is configured for providing transmission and reception of signals over respective transmission and reception frequency bands, and
• wherein h1 is approximately equal to
• m
• 1
• ×
• [
• Φ
• 1
• ±
• (
• ϕ
• ⁡
• (
• Θ
• =
• 0
• )
• -
• ϕ
• ⁡
• (
• Θ
• =
• Θ
• 0
• )
• )
• ]
• ×
• π
• 180
• ×
• λ
• 2
• ⁢
• π
• ×
• 1
• 2
• ,
• where m1 is a positive odd integer,
• Φ1 is a desired amount of phase shift of an outer region of a phase front for reflecting off of the reflector,
• φ is a feed phase contribution for an angle Θ, and
• Θ0 is an angle formed between an axis of the at least one feed and a line connecting a phase center of the at least one feed and an inner edge of the first annular region.